import math
x1,y1,x2,y2=map(float,input().split())
kyori2=(x1-x2)**2 + (y1-y2)**2
kyori=math.sqrt(kyori2)
print(f"{kyori:.8f}") import math math x1,y1,x2,y2=map(float,input().split()) x1 map(float,input().split()) map float input().split() ().split () input split y1 x2 y2 kyori2=(x1-x2)**2 + (y1-y2)**2 kyori2 (x1-x2)**2 + (y1-y2)**2 (x1-x2)**2 x1-x2 x1 x2 2 (y1-y2)**2 y1-y2 y1 y2 2 kyori=math.sqrt(kyori2) kyori math.sqrt(kyori2) math.sqrt math sqrt kyori2 print(f"{kyori:.8f}") print f"{kyori:.8f}" y1,x2,y2=map(float,input().split()) map(float,input().split()) y1 kyori2=(x1-x2)**2 + (y1-y2)**2 (x1-x2)**2 + (y1-y2)**2 kyori2 kyori=math.sqrt(kyori2) math.sqrt(kyori2) kyori y2=map(float,input().split()) map(float,input().split()) y2 x1,y1,x2,y2=map(float,input().split()) map(float,input().split()) x1 x2,y2=map(float,input().split()) map(float,input().split()) x2
import math
x1,y1,x2,y2=map(float,input().split())
kyori2=(x1-x2)**2 + (y1-y2)**2
kyori=math.sqrt(kyori2)
print(f"{kyori:.8f}")
